Process of reacting a tertiary amine with a halogenated copolymer of an isoolefin monomer and a multiolefin monomer, and product thereof



United States Patent 3,011,996 PRDCESS 0F REACTING A TERTIARY AMINE WITH A HALOGENATED COPGLYMER OF AN ISOOLEFIN MONOMER AND A MUL'IIOLEFIN MONOMER, AND PRODUCT THEREOF Irving Kuntz, Roselle Park, and Francis P. Baldwin,

Colonia, N.J., assignors to Esso Research and Engineering (lompany, a corporation of Delaware No Drawing. Filed Apr. 15, 1957, Ser. No. 652,596 11 Claims. (Cl. 260--41.5)

This invention re.ates to themodification of rubbery halogenated copolymers of isoolefins and multiolefins, particularly chlorinated or brominated butyl rubber with certain tertiary amines.

Butyl rubber copolymers comprise a major proportion (preferably about 85 to 99.5 weight percent) of a C to C isocleiin such as isobntylene, 2-methyl-1-butene or 3-methyl-l-butene, etc., with a minor proportion (preferably about 15 to 0.5 weight percent) of a multiolefin of about 4 to 14, preferably about 4 to 6 carbon atoms and are commonly referred to in patents and technical literature as butyl rubber, or GR-I rubber (Government Ru-bber-Isobutylene), for example in textbook Synthetic Rubber by G. S. Whitby. The preparation of butyl rubber is described in Us. Patent 2,356,128 to Thomas et al. The multiolefinic component of the copolymer is preferably a conjugated diolefin such as isoprene, butadiene, dimethylbutadiene, piperylene, or such multiolefins as cyclopentadiene, cyclohexadienes, dimethallyl, allo ocymene, vinyl fulvenes, etc. The copolymer comprising isobutylene and isoprene is preferred, although the copolymer may contain about 0.05 to 20.0, preferably about 0.2 to 5.0 parts by weight based on total reacting comcnomers of such monoolefinic compounds as styrene, pmethyl styrene, alpha methyl styrene, indene,fdihydronaphthalene, dichlorostyrene, p-chlorostyrene, mixtures thereof, etc. Such a copolymer has a Staudinger molecular weight between about 20,000 and 300,000, or a viscosity average molecular weight of about 250,000 to 2,000,000 and a mole percent unsaturation between about 0.5 and 15.0.

In accordance with the present invention, it has now been found that rubbery halogenated isoolefin-multiolefin copolymers such as butyl rubber may be modified by minor proportions of heterocyclic tertiary amines to form thermoplastic materials which may be molded into products having high tensile strengths without the need of added curatives. Such high tensile strength materials may be produced by heating the modified copolymer at a temperature level of between about 80 and 450 F. for between about 0.5 minute and hours.

The halogenated rubbery isoolefin-multiolefin copolymers are produced by carefully chlorinating or brominating these copolymers in a manner which does not substantially degrade the molecular weight thereof. More particularly, in producing halogenated butyl rubber, the halogenation is regulated so that the resulting rubber will contain at least about 0.5 Weight percent (preferably at least about 1.0 weight percent) combined halogen but not more than about X weight percent combined chlm rine or 3.0 X weight percent combined bromine whereand L=mole percent of the multiolefin in the polymer, M =molecular weight of the isoolefin, M =molecular weight of the multiolefin, M =atomic weight of chlorine or bromine.

Suitable halogenating agents which may be employed are gaseous chlorine, liquid bromine, alkali metal hypochlorites or hypobromites, C to C tertiary alkyl hypochlon'tes, sulfur bromides, sulfuryl chloride, pyridinium chloride perchloride, N-bromosuccinimide, alpha-chloroaceto-acetanilide, N,N'-dichloro-5,5 dimethylhydantoin, iodine halides, trichlorophenol chloride, N-chloroacetamide, beta-bromomethyl phthalimide, etc. The preferred halogenating agents are gaseous chlorine, liquid bromine, sulfuryl chloride, sulfuryl bromide, chloro-hydantoins, bromo-hydantoins, iodine monochloride, and related materials.

The halogenation is generally conducted at temperatures of above about 0 to about C., depending upon the particular halogenating agent, for about one minute to several hours. An advantageous pressure range is from about 0.1 to 1000 p.s.i.a., atmospheric pressure being satisfactory. The halogenation may be accomplished preferably by preparing a 1 to 80 Weight percent solution of such copolymers as above, in a substantially inert liquid organic solvent such as a C to C substantially inert hydrocarbon or halogenated derivatives of saturated hydrocarbons; e.g., hexane, mineral spirits, cyclohexane, benzene, chlorobenzene, chloroform, carbon tetrachloride, mixtures thereof, etc. and adding thereto the halogenating agent, which may optionally be in solution, such as dissolved in a substantially inert hydrocarbon, an alkyl chloride, carbon tetrachloride, carbon disulfide, etc. If chlorine gas is employed, it may also be diluted with up to about 50 times its volume, preferably about 0.1 to 5.0 times its volume of a substantially inert gas such as nitrogen, methane, carbon dioxide, etc.

The resulting halogenated isoolefin-multiolefin-containing copolymer may be recovered by precipitation with oxygenated hydrocarbons, particularly alcohols or ketones such as acetone or any other known non-solvent for the rubbery copolymer and dried under about 1' to 760 millimeters or higher of mercury pressure absolute at about 0 to 180 C., preferably about 50 to C. (e.g. 70 C;). Other methods of recovering the chlorinated polymer are by conventional spray or drum drying techniques. Alternatively, the solution of the halogenated butyl rubber may be injected into a vessel containing steam and/ or agitated water heated to a temperature sufficient to volatilize the solvent and form an aqueous slurry of the halogenated butyl rubber. This halogenated butyl rubber may then be separated from the slurry by filtration and drying and recovered as a crumb or as a dense sheet or slab by conventional hot milling and/or extruding procedures. As so produced the halogenated rubbery copolymer has a Staudinger molecular of halogenated copolymer, of certain tertiary amines, optionally in the presence of about 0.01 to 5.0 weight percent based on copolymer of a Lewis acid-type catalyst such as zinc chloride, mercuric chloride, silver nitrate,

The chlorine was added to the reactor through the conduit via the sparger ring. The chlorination was then terminated and the solution containing the chlorinated butyl rubber formed was agitated for an additional 10 minutes.

Oyclopentadiene (6) Isobutylene (92) (8. 2-methyl'outene-1 (95)..-

Kmethylbutene-l 5) or the like. For the purposes of the present invention, 5 The resulting solution of chlorinated butyl rubber was the tertiary amine may be a heterocyclic tertiary amine then water washed three times to remove dissolved bywhich is preferably pyridine or a substituted pyridine of drogen chloride. the general formula: The absolute amount of butyl rubber, benzene solvent N and gaseous chlorine added, as well as the calculated per- 7 10 cent of added chlorine based on polymer and resulting I 0 percent of chlorine combined in the polymer were as (uh- (H)r-n follows:

Percent v Pounds mthc in which 1 is selected from the group consisting of R, OR added g i and OH; R being selected from the group consisting of C to C alkyl, cycloalkyl, aryl, aralkyl and alkaryl; n Butyhubber 17 being an integer of between about 0. and 3. Benzene Solvent Typical tertiary amines, useful for the purposes of the 20 Chkrme "7 present invention include, among others; l-azabicyclo (2.2.2.)octane' isoquinoline' 1 5-diazacyclo-decapentaene' Th r e esultm wate -washed solution COl'ltZLlfllIl chlof l p 'blpyndyl and especlany rinated rubbery butyl rubber M was then injected into R The f g regimen Products fi have 6140 lbs. of an agitated aqueous solution containing 0.5 uuhty as rubber Insulation. m proofed goods wei ht percent based on chlorinated butyl rubber of an In order to more fully lllustrate the present invention, avpilafic pelyoxyethylene ethnr type Wetting agent (i e the following experimental data are g1 Sterox Al), the temperature being maintained at a level CHLORINATED BUTYL RUBBER A of between about 190 and 210 F. (e.g. 200 F.)

A copolymer of about 97% isobutylene an 3% whereby to flash off the benzene solvent and form an r prene having a viscosity average molecular weight of 0 g; 2: 333 25 2353? 212;3 :3322? 32000O was dlssolved in hexane to form Schlrulil aei' l iich was in th: foim of a wet crumb WZS .tlon' To thls polymer a 20 welgh-t percent placeddn a Proctor and Schwartz tray drier maintained (based on the polymer) of liquid snlfuryl chloride as the at 180 F (is C) and dried for ten hours The chlorinatmg agent was added at room temperature. The crumb p' the y was about 1/2 inch The crumb resulting chlorinated mterpolymer was precipitated with w th m I tel dried and com acted minim for acetone, collected and redissolved in hexane three times 8 Co P e y 1 u and ultimately dried and analyzed and found to have a mmutes 5 5?; t i er m1 avmg a To viscosity average molecular weight of 320,000 and to temperature) contain 1.4% chlorine. The physical characteristics of 40 Example I .both zinc oxide and diamine-cured vulcanizates, contain- 400 grams of chlorinated butyl rubber were 1 mg this chlorinated. mterpolymer were excelent' solved in 4000 cc. of chloroform. To this solution were 'CH R AT RUBBERS To added 1 gram of Zinc chloride in 50 cc. of moist acetone Other examples of halogenated isoolefin-multiolefin cofollowed by 200 of Py The Teactlon 1111x911? polymars are'as f ll the amount of i l fi and was then heated at to C. for 26 hours. The IIlOdlmultiolefinin copolymer,halogenation agent, and amount ficd product formed was isolated and any unreacted of halogen combined in the copolymer being tabulated pyridine removed by running the reaction mixture slowly hereinafter: into a large volumeof boiling water. The modified prod- Halo- Halogen genated Isoolefin 1 Multiolefin 1 Halogenation Agent {)he Ill er Isobutylene (98) Isoprene (2) S0261 1.2 chlorine. Isobutylene (95). Isoprene (5.0) C1; in G014 2.5 chlorine. Isobutylene (94). C12 in 001 2.0 chlorine.

1.6 chlorine. 1.5 chlorine. 1.9 chlorine.

Isobutylene 9s) .I

Isobutylene (98) Isoprene (2) Gaseous chlorine N,N-dichloro-5,5-dimethyl hydantoin.

Liquid bromine 0.8 chlorine. 2.8 chlorine. 6.6 chlorine. 1.1 chlorine.

2.3 bromine.

1 NOTE.(%) in all instances is percent by weight.

CHLORINATED BUTYL RUBBER M not was collected by filtration, air dried, and finally dried by hot milling on a rubber mill at 250 to 260 F. for 10 minutes and was found to contain 0.025% nitrogen.

A sample of the modified product was molded at 275 F. for 1 5 minutes and then placed in a cold press for 10 minutes. A portion of 0.014 inch thickness was found to have the following physical properties:

Tensile strength (p.s.i.) 4650 Elongation (percent) 700 The above data show that pyridine modified chloture level of 30 C. and under atmospheric pressure. 76 rinated butyl rubber can be molded into a product of Example 11 100 parts by weight of the modified product of Example I were compounded with 50 parts by weight of .silica and 40 parts by weight of titanium dioxide. The

compounded material was molded under 800 p.s.i. pressure at 275 F. for 15 minutes and then transferred to a cold press and allowed to cool for 10 minutes at room temperature. Physical inspect ons resulting from a test specimen cut from the molded sheet were as follows:

Tensile strength (p.s.i.) 880 Elongation (percent) 225 Modulus at 100% elong. (p.s.i.) 500 Unmodified chlorinated butyl rubber, molded as above, would have a tensile strength of less than 200 p.s.i.

Example III The same general procedure as in Example H was repeated replacing the silica with SRF carbon black and omitting the titanium dioxide with the following results:

Tensile strength (p.s.i.) 1030 Elongation (percent) 535 Modulus at 100% elong. (p.s.i.) 240 The above data show that in carbon black reinforced compounds, the pyridine modified product has useful tensile and elongation properties.

Example IV 100 grams of a brominated butyl rubber having a Mooney viscosity (212 F. for 8 minutes) of 50 and a bromine content of 2.7 weight percent based on butyl rubher, were dissolved in 1,000 cc. of chloroform. This solution was reacted with 49 grams of pyridine at 60 C. for 17 hours. The modified product formed was isolated and recovered as in Example I. Analysis of the product indicated 0.48% nitrogen. A sample of this material was molded at 275 F. for 15 minutes and then in a cold press for 10 minutes. A specimen of 0.015 inch thickness was found to have the following physical properties:

Tensile strength (p.s.i 1380 Elongation (percent) 550 The above data show that pyridine modified brominated butyl rubber molds into a product of good tensile strength and elongation without the need of added curatives.

Example V 100 parts by weight of the modified product of Example I were compounded with 50 parts by weight of SRF carbon black, parts by weight of zinc oxide, 2 parts by weight of sulfur, and 1 part by weight of tellurium diethyl dithiocarbamate and cured for 40 minutes at 307 F., the resulting vulcanizate exhibiting the following physical inspections:

Tensile strength (p.s.i 1280 Elongation (percent) 285 Modulus at 100% elong. (p.s.i 390 The above data show that pyridine-modified chlorinated butyl rubber cures into a product of good physical properties in the presence of conventional butyl rubber curatives. It has further been found that the pyridine-modified chlorinated butyl rubber of the present invention may be cured solely by zinc oxide or covulcanized, particularly in the presence of sulfur, with about 5 to 95 weight percent based on total rubber of such unmodified butyl rubber, natural rubber, rubbery diene-styrene copolymers, rubbery dienc-nitrile copolymers, mixtures thereof, etc. For vulcanization or covulcanization in the presence of sulfur, it is preferred to cure the resulting composition at about 200 to 450 F., preferably at about 250 to 400 F. for between about 0.5 and 90 minutes depending on the temperature employed.

Resort may be had to modfiications and variations of the disclosed embodiments without departing from the spirit of the invention or the scope or" the appended claims.

What is claimed is:

1. A vulcanizate which comprises the reaction product of 100 parts by weight of a halogenated copolymer of 85 to 99.5 wt. percent of an isoolefin and 15 to 0.5 wt. percent of a multiolefin, said copolymer having a mole percent unsaturation of about 0.5-15.0 and containing at least 0.5 wt. percent but not more than one combined atom of halogen per double bond in the polymer, said halogen being selected from the group consisting of chlorine, bromine, and iodine, and 5 to 75 parts by mula:

in which y is selected from the group consisting of R, OR and OH; R being selected from the group consisting of C to C alkyl, cycloalkyl, aryl, aralkyl and alkaryl, n being an integer of between about 0 and 3, said reaction product having been cured to provide a vulcanizate having increased tensile strength.

2. A composition according to claim 1 in which the halogenated copolymer contains at least about 0.5 weight percent chlorine but not more than about 1 combined atom of chlorine per double bond in the copolymer.

3. A composition according to claim 1 in which the halogenated copolymer contains at least about 0.5 weight percent bromine but not more than about three con1- bined atoms of bromine per double bond in the copolymer.

4. A composition according to claim 1 which has been molded in the absence of curatives at a temperature level of between about and 450 F. until it exhibits a tensile strength of at least about 800 p.s.i.

5. A process for modifying a halogenated copolymer of to 99.5 wt. percent of an isoolefin and a 15 to 0.5 wt. percent of a multiolefin, said copolymer having a mole percent unsaturation of about 0.5 to 15.0 and containing at least 0.5 wt. percent but not more than one combined atom of halogen per double bond in the polymer, said halogen being selected from the group consisting of chlorine, bromine, and iodine, which comprises reacting part by weight of said halogenated copolymer at a temperature level of between about 0 and C. with 5 to 75 parts by weight of a heterocyclic tertiary amine having the formula:

at C

"2 6. A process according to claim 5 in which the result- 450 F. until a material having a tensile strength of at least about 800 psi. is produced.

7. A molded thermoplastic vulcanizate having a tensile strength of at least about 800 p.s.i. containing the reaction product of a halogenated copolymer of 85 to 99.5 wt. percent of an isoolefin and 85 to 0.5 wt. percent of a multiolefin, said copolymer having a mole percent unsaturation of 0.5 to 15.0 and containing at least 0.5 wt. percent but not more than one combined atom of halogen per double bond in the polymer, said halogen being selected from the group consisting of chlorine, bromine, and iodine and a heterocyclic tertiary amine having the 7 formula:

8. A product according to claim 7 in which the amine is pyridine.

9. A vulcanized product having an elongation of about 200 to 600% and an extension modulus at 100% e1on-' gation of between about 200 and 600 p.s.i., said product comprising an admixture of at least one inorganic filler and the reaction product of a halogenated copolymer of 85 to 99.5 wt. percent of an isoolefin'and to 0.5 wt. percent of a multiolefin, said copolymer having a mole percent unsaturation between about 0.5 to 15.0 and containing at least 0.5 wt. percent but not more than one combined atom of halogen per double bond in the polymer, said'halogen being selected from the group of chlorine, bromine, and iodine and a heterocyclic tertiary amine having the formula:

10. A .vulcanizate comprising the reaction product of 100 parts by weight of a chlorinated copolymer of to 99.5 wt. percent of an isobutylene and 15 to 0.5 wt. percent of isoprene, said copolymer having a mole percent unsaturation of about 0.5 to 15 .0 and containing about 0.5 to about 2.8 percent chlorine with about 5 to 75 parts by weight of pyridine, said reaction product having increased tensile strength.

11. The process which comprises reacting parts by weight of a chlorinated copolymer of 85 to 99.5 wt. percent of an isobutylene of 15 to 0.5 wt. percent of isoprene, said copolymer containing about 0.5 to about 2.8 percent chlorine with 5 to 75 parts by weight of pyridine at a temperature of about 0 to C. for about ten minutes to fifty hours to provide a reaction product which is capable of being cured to a unitary vulcanizate.

References Cited in the file of this patent UNITED STATES PATENTS 2,451,174 Renter Oct. 12, 1948 2,476,832 Donia July 19, 1949 2,804,448 Hallenbeck Aug. 27, 1957 2,860,118 Nagelschmidt et al. Nov. 11, 1958 

1. A VULCANIZATE WHICH COMPRISES THE REACTION PRODUCT OF 100 PARTS BY WEIGHT OF A HALOGENATED COPOLYMER OF 85 TO 99.5 WT. PERCENT OF AN ISOOLEFINA DN 15 TO 0.5 WT. PERCENT OF A MULTIOLEFIN, SAID COPOLYMER HAVING A MOLE PERCENT UNSATURATION OF ABOUT 0.5-15.0 AND CONTAINING AT LEAST 0.5 WT. PERCENT BUT NOT MORE THAN ONE COMBINED ATOM OF HALOGEN PER DOUBLE BOND IN THE POLYMER, SAID HALOGEN BEING SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE, AND IODINE, AND 5 TO 75 PARTS BY WEIGHT OF A HETEROCYCLIC TERTIARY AMINE HAVING THE FORMULA: 